At present, the code division multiple access (CDMA) system draws extensive attention. More and more researches on the CDMA system are being carried out. The high data rate (HDR) technology, which is also called high rate packet data (HRPD) or 1×EV-DO, is one of 3G technology standards.
In addition, the long term evolution (LTE) technology is considered as the mainstream technology for 4G mobile communication systems. An LTE system uses the orthogonal frequency division multiple access (OFDMA) and multiple input multiple output (MIMO) technologies, thus greatly improving the spectrum utilization and capacity of the communication system. Further, the LTE technology can better support large data download services such as the voice over IP (VoIP) or video calling service.
Because LTE is considered as the next generation mainstream technology, some CDMA operators decide to gradually upgrade the current HRPD network to the LTE network. Therefore, the HRPD and LTE networks may coexist for a long period of time.
The maturity of the multimode terminal paves the way for the interworking between different radio technology standards. A lot of standardization organizations carry out researches on the interworking between multiple radio access technologies, with the focus on the interworking between the HRPD and the evolved universal terrestrial radio access network (EUTRAN).
For the interworking between the HRPD and the EUTRAN, the most basic mobility management is based on the mobility protocol at the network layer. If the terminal has the ability to perform dual radio receiving/transmission, the mobility protocol at the network layer may meet the handover performance requirements of real-time services. If the terminal does not have the ability to perform dual radio receiving/transmission, the interworking between the 3rd Generation Partnership Project (3GPP) network and the non-3GPP network relies on only the mobility protocol at the network layer. Due to the access authentication and authorization of the target system, specific radio negotiation and configuration processes of the target access system, and long handover delay, the handover performance requirements of the real-time services cannot be satisfied. Thus, the handover is classified into the following two types: Type 1: non-optimized handover, and Type 2: optimized handover. The objective of the optimized handover is to reduce the handover delay and improve the performance by performing earlier access authentication and authorization and completing the specific radio negotiation and configuration processes of the target access system. Particularly, the handover between radio access networks (RANs) when the radio link of the air interface is idle is also called reselection.
During the implementation of the interworking between the HRPD and the EUTRAN, the inventor of the present application discovers at least the following problems in the prior art:
Currently, the standard for performing optimized handover from the LTE network to the HRPD network is basically determined, but the standard for performing optimized handover from the HRPD network to the LTE network is not perfect. Therefore, after the mobile terminal reselects from the HRPD network to the LTE network, the mobile terminal may perform a series of abnormal actions because air interface related sub-protocols of the HRPD module of the mobile terminal cannot know that the mobile terminal has already reselected from the HRPD network to the LTE network.